The known intercoolers for motor vehicles are used to cool the combustion air that is compressed by a supercharging assembly—such as, for example, a compressor or turbocharger—in order to further increase its air density. A larger air mass can thus be fed to the engine, as a result of which a greater amount of fuel can be injected, which increases the output of the engine.
Intercoolers usually have a heat exchanger module through which charging air flows. At a network structure of the heat exchanger module, this charging air releases its heat into the ambient air. In many cases, liquid-cooled heat exchanger modules are also used for intercoolers.
If exhaust-gas turbochargers are used as supercharging assemblies, their compression efficiency depends greatly on the respective operating state of the motor vehicle. To improve the compression, a so-called step-by-step supercharging is therefore used to an increasing extent, i.e., the compression of the charging air is ensured by two supercharging assemblies, which in each case are optimized in various operating states of the motor vehicle. In this case, in general one of the supercharging assemblies runs continuously, while a second assembly is turned on only under specific operating states.
If such a multi-step supercharging is used in combination with an intercooler that is known from the prior art, the compressor exhausts of the two supercharging assemblies, from which the compressed air exits, must first be brought together before the charging air can be fed to the intercooler. This disadvantageously leads to an increase in the installation space requirement. In addition, with such a design, the problem exists that the volume of the heat exchanger module of the intercooler has to be optimized for the amount of charging air that accumulates during simultaneous operation of the two supercharging assemblies. For the operation of an individual supercharging assembly, this volume is designed too large, however, which leads to a loss of power, and, in the event of load variations of the motor vehicle engine, to impaired performance.
The object of this invention is thus to provide an intercooler for a motor vehicle that overcomes the above-mentioned drawbacks in a step-by-step supercharging. In particular, the object of the invention is to provide an intercooler that is built in an especially compact manner.